This invention relates to an optical disc and an apparatus for recording signals on the disc. More particularly, it relates to an optical disc adapted for limiting the number of times of recording or recording time duration, and an apparatus for recording signals on the disc.
Recently, attempts have been made to evolve a write-once type optical disc or a rewritable optical disc, on which musical sound data may be written according to the data format comparable with that used for a compact disc (CD).
This write-once type optical disc has a data record region in which musical sound data may be written spirally circumferentially, and a lead-in region disposed on the inner peripheral side of the data record region and in which table of contents (TOC) data for the musical sound data may be written, with the musical sound data and the table of contents data therefor being written only once by the user. The musical sound data written in the data record region of the write-once type disc may be reproduced on the basis of the table of contents data written in the lead-in region.
Meanwhile, such write-once type disc has an extremely large capacity of the data record region into which the musical sound data of a large number of musical pieces can be written.
However, with a view to simplifying the control or superintention of the musical sound data written into the data record region, there is also a demand for the write-once type optical disc in which only the musical sound data of a predetermined number of musical pieces can be written in its data record region.
There has also been known a rewritable disc in which audio or video signals are recorded by taking advantage of magnetic induction or the photomagnetic effect (Kerr effect). While the record signals are rewritten in this rewritable disc by a recording system, it is frequently desirable to limit the number of times of rewriting or the cumulative recording time duration.
The present invention is useful whenever it is desired to limit the recording capacity of the disc. For example, if a disc is of the type which is reliably written only once, without a capacity for erasure and rewriting, or overwriting, the present invention prevents any attempt to perform erasure and overwriting. Also, even in the case of a disc which is capable of overwriting, or erasure and rewriting, it is sometimes desirable to limit the number of writings of any recordable area to exactly once, to avoid any undesirable residual effects from a previous recording, and/or to comply with other special requirements which may be imposed, such as, for example, consideration for copyright protection of material which may be recorded on the disc.